Method of producing a multicolor screen for the production of photographic color pictures



July 9, 1935 2,007,282

F. H. MLLER METHOD PRODUGING A MULTICOLOR SCREEN FOR THE PRO TION O HOTOGRAP COLOR PICT S led June 1931 Sheets-Sheet 1 F. H. MULLER 2,007,282 PRO CING A MULTICOL SCREEN FOR THE July. 9,` 1935 METHOD PRO TIO F PHOTOGRAP LOR PICTURES Filed June 1931 2 Sheets-Sheet 2 Illllll Illllll lllllli llllll illll||`|I Patented July 9, 1935 UNITED STATES PATENT OFFICE METHOD OF PBODU SCREEN FOR THE CING A MULTICOLOR PRODUCTION'OF PHO- TOGBAPHIC COLOR PICTURES Franz- Hubert Mller, Bielefeld, Germany signor Yto Drkopp-Werke A.G., Bielefeld,

Germany Application June i9, 1931, serial No. 545,492

Germany June 1, 1931 4Claims.

form. In the case of line screens the colors are Y applied successively in several layers. The present invention relates tothe production of a line screen and consists substantially in that a multicolored screen of absolute regularity and any desired screen flneness is produced in only one layer in that the different screen colors are applied by partly hardening, printing the line screen, washing out the vvhardened lines, coloring theinon-hardened portion with another color.

Several embodiments of the invention are illustrated by way of example in theaccompanying drawings, in which:-

Figs. 1 to 6 show the diierent stages of one 20 method of/producing a two-color screen in only one layer.

Fig. 7 shows a screen interspersed with pure whites.

Figs.' 8 and 9 show the stages of a modiied method for. producing a two-color screen.

Figs. to 14 show the stages of a third method for producing a two-color screen.

Figs. and 16 show the stages of still a further method.

Figs. 17 to 22 show the different stages for producing a three-color screen in only one layer. According to Figs. 1 to 6 the llm or plate Il is coated with gelatine 2, which, in the case of a two-color screen is colored, for example red (Fig. 2) which can be subsequently washed out. The gelatine is then sensitized with potassi or ammonium bichromate solution and dried. After the drying a vertical screen 3 (Fig. 3) is printed by exposure on the layer thus prepared. Owing to this exposure the gelatine hardens at the portion upon which the light impinges. After the printing the plate 'is washedyuntii the color is entirely washed out from the non-hardened portions. 'Ihe portions from which the red has been removed are colored with another color, for example ultramarine blue, which must be capable of adhering on the non-hardened portions. The lm or plate is then placed in a bath of 'potassium permanganate. 'I'his is effected for the purpose of removing by oxidation the second color which may have settled to the portions of the gelatine colored and'hardened. The whole layer however becomes'sllghtly brown by the potassium permanganate bath and -this 55 brown coloring ls removed by a suitable bath of (Cl.A 95-81.5)

potassium inetabisulphite, the colors are thus rendered purer and brighter by this bath. The lm is then washed, dried, coated, with a neutral varnish 5 (Fig. 5) and a very sensitive panchromatic emulsion 6 (Fig. 6) poured thereover. 5

Fig. 7 is the graphic illustration of a. multi-y colored screen interspersed by pure whites.

According to Figs. 8 and 9 for producing a twocolor screen the ilm or plate is coated with a light sensitive emulsion containing silver, on which the screen is printed, developed, fixed and washed; it is then steeped in a red, color, and the silver grain converted into silver bromide, after which the grey lines are washed out in the fixing bath. The non-hardened 'color is then washed out, colored blue, the overlapping color is removed by oxidation, after which it is varnished and coated with emulsion.

According to Figs. 10 to 14 the lm or plate is coated with a silver bromide or chloride emulsion, on which the screen is printed; the black silver screen is then converted into a ferrocyanide copper screen and colored red, and is then washed. A second layer of silver bromide or silver chloride emulsion is then applied, exposed from the rear side of the plate or lm, and the black screen converted into a ferro-cyanide copper screen, after which a blue color is applied;

`the plate being then washed, varnished and coated with pan-chromatic emulsions.

As shown in Figures 15 and 16, the reference character 8 designates an emulsion containing a silver image, which was obtained by silver bromide sensitization, exposure, development and xing, and is carried by a paper support 1. The layer 2 on the suppOI't l is colored red and treated with the usual solution for ozcbrome work. The layers 8 and 2 are pressed into contact while wet and later separated. 'l'he red color is washed out of the unhardened gelatine in layer 2 and this is redyed green, the overlapping color removed by oxidation, the layer varnished and coated with a highly sensitive panchromatic emulsion.

'I'he color screens can evidently be produced in a different sequence of operations, in that the screen is rst painted on the prepared plate, then colored with a suitable color, after which the unhardened portions are dissolved or washed out and the second color applied.

Figs. 17 to 22 show the production of a threecolor screen in only one layer. The glass plate covered with gelatine is colored red, sensitized by means of a. bichromate and dried. After the drying a vertical screen 9 is printed on the plate, the dark lines ofthe screen being of half the width iol-manure 'PillHandbndL wlnciusb'runingJochstamllaim dthelightlines. Ai'tertheprinting theplateis washed until the color f from the nonhardened portions (Fig. 18)'. ese portions are then colored with ultramarine blue, whereupon the plateis againrsensitisedby means of abiehxolnate and dried. A horizontal screen Il in whichthelightanddarklinesareuniformly vwileisthenprintedonthepl. Theunhardl'il.'lcanbeemnloyed,purewhitesareprinted beaidesthediiier'eitcolorsmordertobrighten the paper because in the additive paper mesthethreeadditivecolorsdonotmixto white. Y Inordertocorrespondingiy brightenthelayeratthelightportionsthelight positive screen intersected by pure whites either.

by hardening thegelatlne under a suitable line screenbeforethecoioring,orbvyapplyingapro-4 teetingm screen with some water repelling sub- Theeolorsreferredtohereinasbeingbleached by potsssiumpermanganate are organicl colors whiehbleachmoreorlesswhensotreated. 'Ihe reaetimisparticnhrlystrongandrapidinthe easedeolorsemploy'edineoloredphotography. for in the publication, -publishedbyll'arbwerke vorm.

ma iilmproducedaccording totbemethodabovedescribeditispossibleto convert the negative directly into a positive. -Howevelzitnenveeoniesaretobeprodweda nlmnmbeemployed'preparedexactlylikethe nimnsedi'ortakingthepicturmbutcoatedwith oniyasiighilynisiihepanchromsticemulsion.

Idainn- LAmetlmdf'producingamulti-colorscreen forphotographicpietmuinsensitizingaeolloidlanrwithsilverbmmideineopying purewiute .lines in said layer, in applying in this same layer different screen colors by silver bromide sensitizing for coloring the layer, partly hardening the same and copying a line screen therein, then washing to remove the unhardened lines and subsequently coloring the washed unhardened portions with another color.

2. A method for producing a. multi-color screen for photographic pictures, consisting in sensiti'zing a layer of gelatine with silver bromide, in copying pure white lines on said layer, in applying the layer'of gelatine to a film, in coloring the applied layer with one color, sensitizing by silver bromide and drying the same, in copying the screen negative thereof, in washing out the nrst color from the unhardened portions, in applying a second color to the layer, in dipping the iilm ilrst in permanganate of potassium and then in potassium metabisulpbite, in washing, drying and coating with varnish, and in applying a panchromatic highly sensitive emulsion to the layer.

3. Amethod for producing a multi-color screen for photographic pictures, consisting in sensitizing a layer of gelatine with silver bromide, in copying pure whites in said layer, in coloring said layer with one color, in producing s screen on silver bromide paper, in applying said screen to the layer according to the osobrom process, in removing the silver bromide paper, in washing out the unhardened color, in applying another color, in removing the covering color, in varnishing the layer and in pouring thereover a highly sensitive panchromatlc emulsion.

4. A method tor producing a three-color screen for photographic pictures, consisting in coating a film with a plastic layer. in copying pure whites on this layer, in coloring -this layer red, sensitizing the same with silver bromide, copying -thereon a screen having one part light and two partsl dark. washing out the unhardened red color, applying blue to the unhardened washed out portion, again sensitizing the nlm, copying thereon atrightanglestotheiirstscreenasecondline screen having transparent and opaque linesv of equal thic, in washing out the unhardened blue portions, in coloring yellow to produce green,

Vinremovingthecoveringcolorinapplylngacoat of varnish, and pouring a highly sensitive chromatic emulsion thereover.

FRANZ HUBERT MULLER. 

